This invention relates to an amplifier arrangement for amplifying an input signal, comprising:
a first and a second field-effect transistor of a first conductivity type, and PA0 a driver circuit for driving the first and the second transistor dependent on the input signal. PA0 the driver circuit is coupled to a first power-supply terminal and has a first and a second output terminal, PA0 the drain-source path of the first transistor is coupled between the first output of the driver circuit and a second power-supply terminal, PA0 the drain-source path of the second transistor is coupled between the second output of the driver circuit and the second power-supply terminal, and PA0 the drain of the first transistor is coupled to the gate of the second transistor and through a resistive element to its gate, which is coupled to the second power-supply terminal through a capacitive element.
As is known, step-function signals, for example, digital squarewave signals, may be thought to consist of an infinite sequence of harmonic signals. For amplifying such signals it is, in principle required to use amplifiers having a maximal bandwidth because otherwise the waveform of the amplified output signal will differ excessively from that of the input signal to be amplified. This specifically results in the signal edges being affected.
The step-function response of an amplifier arrangement can be corrected inductively, for example by arranging an inductance parallel to the load of the amplifier arrangement, inter alia to cancel the effect of stray and wiring capacitances. Such an inductance speeds up the charging (or discharging) process of a capacitive load or the capacitive component thereof, which improves the steepness of the edges of the step-function signal. The edge steepness of a step-function signal is represented inter alia by its rise time, which is to be understood to mean the time required for a signal to rise from 10% to 90% of its final steady value.
In integrated circuits inductances cannot be formed on the substrate of the circuit, so that these elements have to be added externally to the integrated circuit. Such external elements are generally less desirable.